50 research outputs found
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Effects of nitrogen and sulfur fertilization on free amino acids, sugars, and acrylamide-forming potential in potato
Nitrogen (N) fertilizer is used routinely in potato (Solanum tuberosum) cultivation to maximize yield. However, it also affects sugar and free amino acid concentrations in potato tubers, and this has potential implications for food quality and safety because free amino acids and reducing sugars participate in the Maillard reaction during high-temperature cooking and processing. This results in the formation of color, aroma, and flavor compounds, but also some undesirable contaminants, including acrylamide, which forms when the amino acid that participates in the final stages of the reaction is asparagine. Another mineral, sulfur (S), also has profound effects on tuber composition. In this study, 13 varieties of potato were grown in a field trial in 2010 and treated with different combinations of N and S. Potatoes were analyzed immediately after harvest to show the effect of N and S fertilization on concentrations of free asparagine, other free amino acids, sugars, and acrylamide-forming potential. The study showed that N application can affect acrylamide-forming potential in potatoes but that the effect is type- (French fry, chipping, and boiling) and variety-dependent, with most varieties showing an increase in acrylamide formation in response to increased N but two showing a decrease. S application reduced glucose concentrations and mitigated the effect of high N application on the acrylamide-forming potential of some of the French fry-type potatoes
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Effects of water availability on free amino acids, sugars, and acrylamide-forming potential in potato
Irrigation is used frequently in potato cultivation to maximize yield, but water availability may also affect the composition of the crop, with implications for processing properties and food safety. Five varieties of potatoes, including drought-tolerant and -sensitive types, which had been grown with and without irrigation, were analyzed to show the effect of water supply on concentrations of free asparagine, other free amino acids, and sugars and on the acrylamide-forming potential of the tubers. Two varieties were also analyzed under more severe drought stress in a glasshouse. Water availability had profound effects on tuber free amino acid and sugar concentrations, and it was concluded that potato farmers should irrigate only if necessary to maintain the health and yield of the crop, because irrigation may increase the acrylamide-forming potential of potatoes. Even mild drought stress caused significant changes in composition, but these differed from those caused by more extreme drought stress. Free proline concentration, for example, increased in the field-grown potatoes of one variety from 7.02 mmol/kg with irrigation to 104.58 mmol/kg without irrigation, whereas free asparagine concentration was not affected significantly in the field but almost doubled from 132.03 to 242.26 mmol/kg in response to more severe drought stress in the glasshouse. Furthermore, the different genotypes were affected in dissimilar fashion by the same treatment, indicating that there is no single, unifying potato tuber drought stress response
Isolation of novel PSII-LHCII megacomplexes from pea plants characterized by a combination of proteomics and electron microscopy
This work was supported by the Italian Ministry of Education, University and Research, “Futuro in Ricerca 2013” program RBFR1334SB to CP
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The acrylamide problem: a plant and agronomic science issue.
Acrylamide, a chemical that is probably carcinogenic in humans and has neurological and reproductive effects,
forms from free asparagine and reducing sugars during high-temperature cooking and processing of common
foods. Potato and cereal products are major contributors to dietary exposure to acrylamide and while the food
industry reacted rapidly to the discovery of acrylamide in some of the most popular foods, the issue remains
a difficult one for many sectors. Efforts to reduce acrylamide formation would be greatly facilitated by the
development of crop varieties with lower concentrations of free asparagine and/or reducing sugars, and of best
agronomic practice to ensure that concentrations are kept as low as possible. This review describes how acrylamide
is formed, the factors affecting free asparagine and sugar concentrations in crop plants, and the sometimes
complex relationship between precursor concentration and acrylamide-forming potential. It covers some of the
strategies being used to reduce free asparagine and sugar concentrations through genetic modification and other
genetic techniques, such as the identification of quantitative trait loci. The link between acrylamide formation,
flavour, and colour is discussed, as well as the difficulty of balancing the unknown risk of exposure to acrylamide in
the levels that are present in foods with the well-established health benefits of some of the foods concerned.
Key words: Amino acids, asparagine, cereals, crop quality, food safety, Maillard reaction, potato, rye, sugars, wheat
Acrylamide: new European risk management measures and prospects for reducing the acrylamide-forming potential of wheat
Acrylamide (C3H5NO) is a processing contaminant formed from free asparagine and reducing sugars during high-temperature cooking and processing. It is a Group 2A carcinogen, and the European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain (CONTAM Panel) has expressed concern for the potential tumor-inducing effects of dietary exposure. Potato, coffee, and cereal products are the major contributors to dietary acrylamide intake. The European Commission recently introduced strengthened risk management regulations for acrylamide in food, including compulsory mitigation measures and new benchmark levels. Measures adopted to reduce acrylamide formation in potato chips in Europe resulted in a 53% decrease from 2002 to 2011. However, since 2011 there has been a leveling off, suggesting that the easy gains have already been made. Acrylamide levels in chips are influenced by seasonal and geographical factors, making regulatory compliance more difficult. In cereals, acrylamide formation is determined by free asparagine concentration, and this differs substantially between varieties. We would support the inclusion of information on grain asparagine concentration in variety descriptions. However, crop management, including ensuring good disease control and sulfur sufficiency, is also important. A key enzyme in asparagine synthesis is asparagine synthetase. Wheat has four asparagine synthetase genes, TaASN1–4. Gene expression and biochemical data have identified TaASN2 as a prime target for genetic interventions to reduce wheat’s acrylamide-forming potential